Hyunsik Jeong
- @RBTree_
- rbtree.blog
- [email protected]
- rbtree
- Seoul, South Korea
I began my journey in information security with PLUS, a university club at POSTECH in South Korea. I mainly studied reverse engineering and cryptography, and achieved notable results through CTF competitions, including being a finalist of the DEF CON CTF for four consecutive years. After completing my undergraduate studies, I earned my Master’s degree at the Graduate School of Information Security, KAIST, under the supervision of Prof. Yongdae Kim and Prof. Insu Yun. Most recently, I worked at Theori, and I continue to compete in CTFs with perfect blue, achieving impressive results.
Work Experience
Senior Researcher
- Wrote numerous challenges for Dreamhack CTFs, including Dreamhack Invitationals
- Conducted research on diverse topics, and integrated the results into Dreamhack lectures
Senior Researcher
- Ransomware research - mainly on breaking cryptographic features
- Cryptographic analysis and offensive research
Software Engineer
- Mainly developed the blockchain called CodeChain (Link) in Rust
- Developed blockchain node APIs in TypeScript
- Studied various cryptographic methods used in blockchain technologies
Research Intern
- Interned at Netmarble AI Revolution Center (NARC)
- Studied reinforcement learning algorithms, including TRPO & PPO
Projects
Analysis of the Correctness of Qualcomm Hexagon Emulators and Decompilers via Differential Testing
For the master thesis. Analyzed Hexagon emulators (hexagon-sim from the Hexagon SDK, QEMU) and a decompiler (binja-hexagon) with the differential testing tool.
Verifiable Gacha System
A class project. Built a gacha platform with a VRF (verifiable random function). Users can fully access gacha logs, including verifiable random values. Still, only the server can generate random values.
Awards
2nd place
1st place
1st place
2nd place
1st place
1st place
1st place
1st Place
2nd Place
1st Place
1st place
Finalist
1st place
1st place
1st place
1st place
Finalist
1st place
1st place
1st place
1st place
Finalist
Finalist
1st place
Finalist
Finalist
26th place
10th place
Gold prize
Written Challenges
Asian Cyber Security Challenge (ACSC)
Blue Water CTF
pbctf
CODEGATE CTF
[Finals] Cutter
[Finals] Hidden Command Service